Police have been asked to investigate suspicions that the phone of rail union leader Bob Crow has been hacked into by journalists, it was revealed today.

Lawyers acting for the general secretary of the Rail Maritime and Transport union have written to the Metropolitan Police asking them to look into suspicions that Mr Crow's phone may have been hacked into between the year 2000 and the present day.

Mr Crow said: "RMT has had suspicions that journalists may have had access to private information about my movements and my union's activities that date back to the year 2000 and we are now asking for the police, as part of their renewed investigation, to disclose to us any evidence or information that they may have uncovered in respect of the News of the World."

A string of politicians and showbiz figures have previously claimed that their phones were tapped, but this is the first time a union leader has raised suspicions.

It is understood that Mr Crow became worried that information about his movements had been accessed without his knowledge.

The union leader has been involved in a number of high-profile transport disputes in recent years, including strikes on London Underground.